Widespread and Efficient Transduction of Spinal Cord and Brain Following Neonatal AAV Injection and Potential Disease Modifying Effect in ALS Mice

Abstract

The architecture of the spinal cord makes efficient delivery of recombinant adeno-associated virus (rAAV) vectors throughout the neuraxis challenging. We describe a paradigm in which small amounts of virus delivered intraspinally to newborn mice result in robust rAAV-mediated transgene expression in the spinal cord. We compared the efficacy of rAAV2/1, 2/5, 2/8, and 2/9 encoding EGFP delivered to the hindlimb muscle (IM), cisterna magna (ICM), or lumbar spinal cord (IS) of neonatal pups. IS injection of all four capsids resulted in robust transduction of the spinal cord with rAAV2/5, 2/8, and 2/9 vectors appearing to be transported to brain. ICM injection resulted in widespread expression of EGFP in the brain, and upper spinal cord. IM injection resulted in robust muscle expression, with only rAAV2/8 and 2/9 transducing spinal motor and sensory neurons. As proof of concept, we use the IS paradigm to express murine Interleukin (IL)-10 in the spinal cord of the SOD1-G93A transgenic mouse model of amyotrophic lateral sclerosis. We show that expression of IL-10 in the spinal axis of SOD1-G93A mice altered the immune milieu and significantly prolonged survival. These data establish an efficient paradigm for somatic transgene delivery of therapeutic biologics to the spinal cord of mice.

Astroglia acquires a toxic neuroinflammatory role in response to the cerebrospinal fluid from amyotrophic lateral sclerosis patients

“…Vasoactive intestinal peptide (VIP) exerts its immune modulatory actions by regulating IL-10 as well as neurotrophic factors in an mSOD1 model of ALS [45]. Similarly, Ayers et al [46] showed that IL-10 expression in the spinal axis prolonged the survival of SOD1-G93A mice. Thus, reduced expression of IL-10 protein component despite the up-regulation of its mRNA levels hints towards the inability of astrocytes to counter the ALS-CSF induced neurotoxic insult and may be denoted as a “quasi-compensatory” response, which requires further investigation.…”

Management of Neuroinflammatory Responses to AAV-Mediated Gene Therapies for Neurodegenerative Diseases

“…While both AAV9 and rh10 show high transgene expression throughout the brain including spinal cord regions, AAV9 shows the greatest rostral-caudal distribution and spreads to the contralateral (un-injected) hemisphere by undergoing axonal transport [57]. Studies in animal models of SMA [42], amyotrophic lateral sclerosis (ALS) [63], MPS IIIB [64], and others show that a systemic injection of AAV9 in neonatal mice results in transgene expression across key CNS substructures and neuronal subtypes such as motoneurons along with improvements in disease-related phenotypes. However, systemic injections in adult mice still result in limited expression and a shift in target cell subtypes, with preferential expression in astrocytes over neurons [61,65,66].…”

Harnessing Immunoproteostasis to Treat Neurodegenerative Disorders

“…Notably, mouse-modeling studies conducted to date often reveal conflicting results of effects of modulating innate immune activation states in neurodegenerative disease models (reviewed in Czirr and Wyss-Coray, 2012. Numerous studies show beneficial effects of an immune-suppressing manipulation and harmful effects of an immune activating manipulation, but multiple studies show the opposite effects or show that that the outcome is dependent on the disease model; for select recent examples of such conflicting data, see Ayers et al, 2015;Chakrabarty et al, 2015;Guillot-Sestier et al, 2015;Heneka et al, 2013;Venegas et al, 2017;Wendeln et al, 2018.). Future studies, which more systematically evaluate how a given immune manipulation alters the phenotype, as described above, will hopefully help build consensus regarding how these preclinical studies inform immune-modulatory therapeutic approaches to neurodegenerative disease.…”